CO2 levels in atmosphere hit historic high

Updated
May 23, 2013 19:36:00

Global greenhouse gases in the atmosphere have reached an ominous milestone that's unprecedented in human history. At the Mauna Loa observatory in Hawaii, the daily reading of carbon concentrations has now reached a level that hasn't been seen in more than 3 million years. CO2 levels in the atmosphere have hit 400 parts per million. The last time it reached this level, temperatures rose by between three and four degrees and sea levels were between five and 40 metres higher than today.

ELIZABETH JACKSON: Global greenhouse gases in the atmosphere have reached an ominous milestone that's unprecedented in recorded human history.

At the Mauna Loa observatory in Hawaii, the daily reading of carbon concentrations has now reached a level that hasn't been seen in more than 3 million years: CO2 levels in the atmosphere have hit 400 parts per million.

The last time it reached a level like this, temperatures rose from between three and four degrees and sea levels were between five and 40 metres higher than today.

John Connor, the CEO of the Climate Institute, explained to AM's Ryan Wittingslow why the figure is so significant.

JOHN CONNOR: Well, this is a measure of the heat-trapping greenhouse gas of carbon dioxide in the atmosphere. And humanity has had its civilisation when it's been between 200 and 300, but since the industrial revolution, we've been increasing those levels by burning fossil fuels and this has now hit a historic mark of 400, which really hasn't been seen for hundreds of thousands, if not millions of years.

RYAN WITTINGSLOW: So what are the implications of these kinds of concentrations? What can we look forward to?

JOHN CONNOR: Well look, this has been part of a steady trend upwards, and now we've passed this 400 parts per million marker in Hawaii, and the implications really are what we've started to see some of now, the climate impacts - more and more extreme weather events, greater climate risks more generally. And so this is endangering human safety, security. There's a whole host of issues here which we just need to recognise, we need to take serious action about, and I think slowly, investors and business around the world are starting to do that. But we've got to take some significant action and putting a price on this carbon dioxide which to date, companies have been polluting with our atmosphere for free.

Of course, we've just changed that somewhat here in Australia.

RYAN WITTINGSLOW: So do you think the carbon tax is a sufficient response to this kind of problem?

JOHN CONNOR: Well, what the carbon laws do is we've started with a price, which is already having an impact in terms of emissions from our energy sector. But also importantly from 2015, set a limit on carbon dioxide, carbon pollutants, and have that going down at least 12 million tonnes a year.

That's a very important part of the architecture, and we need to team that up with other similar carbon markets emerging around the world and starting up - there's a few pilots starting in China.

But really, it's the ambition of action which we need to drive home.

Globally, we need to peak the still-rising levels of global pollution this decade and then drive it down to near-zero by 2050.

ELIZABETH JACKSON: That's John Connor, the CEO of the Climate Institute, speaking to Ryan Wittingslow.

EDITOR'S NOTE (15 May 2013): A specific date for when the 400 PPM reading was recorded was not referred to in the original story, however the story was based on information from the US National Oceanic and Atmospheric Administration (NOAA) which had publicly advised that the 400 PPM reading was recorded on 9 May 2013. Subsequent to the broadcast, the NOAA revised the reading for 9 May to below 400 PPM. However, the NOAA has released further data showing 400 PPM has been recorded on other dates in May 2013.